The present invention relates to a battery pack, which includes a control circuit that controls charging a battery, and a battery charger.
Secondary batteries (batteries), such as nickel-metal-hydride batteries, lithium-ion batteries, etc., have predetermined temperature ranges appropriate for use. If such secondary battery (battery) is used outside the appropriate temperature range, disadvantages may occur, such as lowered charging efficiency, shortened battery life, etc.
Accordingly, some battery chargers for charging these types of batteries are configured to discontinue charging the battery when a detected battery temperature deviates from an appropriate temperature range or rapidly rises while charging.
Other battery chargers are known as being configured to control battery-charging current so that an increase in the battery temperature becomes constant. The battery charger determines that the battery has been fully charged when the increase in the battery temperature is not able to be controlled to be constant any more or when the battery temperature reaches a target temperature, and the battery charger then completes charging (see, for example, Japanese Patent Publication Application No. 2001-136675).